Effect of Water on the Compressive Strength of Bituminous Mixes

Bitumen is widely used for the construction of wearing course of flexible pavement. Strength of bituminous mix reduced by the loss of adhesive bonds resulting from the action of water. This investigation is to carry out the effect of soaking periods on the compressive strength of compacted bituminous mixes with reclaimed polyethylene and reclaimed PVC. Mix -I contain pure bitumen, Mix -II contain bitumen with 10 % reclaimed polyethylene and Mix -III contain bitumen with 7.5% reclaimed PVC were selected for this study. Test specimens were prepared and tested according to the procedures specified by AASHTO T167 (1986). Addition of 10% reclaimed polyethylene increase the Marshall Stability by 92% than the pure bitumen. Otherwise, 7.5% WPVC increases Marshal Stability by 76% than the pure bitumen. The index of retained strength for Mix -I, Mix -II and Mix -III were 84%, 93%, 86% respectively after 24 hrs soaking. These experimental values were above the acceptable recommended limit 75% (specified by Asphalt Institute 1981) for the modified bitumen. Hence the investigation finds the use of Reclaimed polyethylene and PVC as modifier of bituminous mixes (Asphalt).